1. Field of the Invention
The present invention relates to a laser beam generation control system for an optical mark scanner device, and particularly to a laser beam generation control system for an optical mark scanner which can shorten a generation period of a laser beam thereby to prolong a laser diode's life.
2. Description of the Related Art
In recent years, as represented by a point-of-sales system in the retail industry, utilization of bar codes has become wide-spread and the necessity of a bar code scanner that is more compact, smaller in size, less expensive and has lower power consumption has grown rapidly. For this reason, a laser diode has been developed for a laser beam source and is being used in place of a helium-neon laser oscillator.
Whereas such a laser diode has the advantage that it can be miniaturized in comparison with a helium-neon laser oscillator and can be driven with a low consumption of power, attention is now directed to the life of the laser diode. That is, the life of the laser diode is relatively shorter, and is dependent on a generation time or a burning time and it is necessary to substitute a new laser diode at regular intervals.
Therefore, a laser diode having a long life is desired.
An optical mark reader device such as a bar-code scanner is an input device that illuminates the bar code symbols on tags or products and then detects the reflected light from the bar code symbol. The scanner is passed across the code or the object containing the code is passed across the scanner. Fixed-beam scanners are used to monitor the movement of materials.
In general, in a bar code scanner, the laser diode is turned on only when a bar code is read, and a generation period of the laser thereby is shorted to prolong its life. That is, when the bar code is read, the generation of the laser is generally stopped, and when an article which is passed into a reading space is detected by an optical sensor, which is regarded as an item sensor or an article sensor, or when a reading operation is turned ON, the laser diode is turned ON, thereby to shorten the laser generation time of the laser diode and prolong the life thereof.
Regarding a method for utilizing an item sensor, there are problems in that the operational function is influenced by sensor performance, the provision of the sensor makes the apparatus large in scale and correspondingly, further, can be expensive depending on the manufacturer of the apparatus.
Regarding a method for turning ON/OFF a laser diode by means of a trigger switch, there are problems in that it is necessary to activate a switch whenever a bar code is read and the operation thereof can produce an error such that the bar code is read more frequently than necessary thereby imposing excessive work on the operator.